Please use this identifier to cite or link to this item:
|Title:||Discovery of a stripped red giant core in a bright eclipsing binary system|
|Authors:||Maxted, P. F. L.|
Anderson, D. R.
Burleigh, M. R.
West, R. G.
Collier Cameron, A.
Gänsicke, B. T.
Marsh, T. R.
O'Toole, S. J.
Østensen, R. H.
|Publisher:||Oxford University Press (OUP), Royal Astronomical Society|
|Citation:||Monthly Notices of the Royal Astronomical Society, 2011, 418 (2), pp. 1156-1164|
|Abstract:||We have identified a star in the Wide Angle Search for Planets (WASP) archive photometry with an unusual light curve due to the total eclipse of a small, hot star by an apparently normal A-type star and with an orbital period of only 0.668 d. From an analysis of the WASP light curve together with V-band and IC-band photometry of the eclipse and a spectroscopic orbit for the A-type star we estimate that the companion star has a mass of 0.23 ± 0.03 M⊙ and a radius of 0.33 ± 0.01 R⊙, assuming that the A-type star is a main-sequence star with the metallicity appropriate for a thick-disc star. The effective temperature of the companion is 13 400 ± 1200 K from which we infer a luminosity of 3 ± 1 L⊙. From a comparison of these parameters to various models we conclude that the companion is most likely to be the remnant of a red giant star that has been very recently stripped of its outer layers by mass transfer on to the A-type star. In this scenario, the companion is currently in a shell hydrogen-burning phase of its evolution, evolving at nearly constant luminosity to hotter effective temperatures prior to ceasing hydrogen burning and fading to become a low-mass white dwarf composed of helium (He-WD). The system will then resemble the pre-He-WD/He-WD companions to A- and B-type stars recently identified from their Kepler satellite light curves (KOI-74, KOI-81 and KIC 10657664). This newly discovered binary offers the opportunity to study the evolution of a stripped red giant star through the pre-He-WD stage in great detail.|
|Rights:||Archived with reference to SHERPA/RoMEO and publisher website. This article has been accepted for publication in Monthly Notices of the Royal Astronomical Society ©: 2011 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved.|
|Appears in Collections:||Published Articles, Dept. of Physics and Astronomy|
Files in This Item:
|MNRAS-2011-Maxted-1156-64.pdf||Publisher version||791.73 kB||Adobe PDF||View/Open|
Items in LRA are protected by copyright, with all rights reserved, unless otherwise indicated.